This invention relates to a deep well down-hole pumping system and in particular to an improved down-hole water release valve assembly for draining the pipe prior to removing the system from a well.
When problems occur in down-hole pumps, it is necessary to remove both the pump an pipe for repair or replacement of the component parts by pulling the entire system out of a well. Since the pump is at the bottom of the pipe, both are usually filled with water. The water therefore adds a substantial weight to the system. It is a common practice to lighten the load by draining the water from the pipe prior to removal. Many down-hole devices have been proposed to accomplish this. A typical arrangement is to secure the bottom of the delivery pipe to the pump section by a quick disconnect latch. This approach separates the flow from the pump to the pipe and thus allows the pipe to drain. An arrangement like this is disclosed in U.S. Pat. No. 4,595,061 which describes a horizontal drain in the sidewall of the pipe above the pump. The drain leads into a Tee leaving its main line vertical. A slide valve, such as a pipe, is slidably fitted into the Tee. A cable extending from ground level connects to the slide valve so that upon pulling, the drain is uncovered and the pipe drains. The cable may also be connected to the pump to aid in pulling the pump out of the well. Still another prior design is disclosed in U.S. Pat. No. 4,103,739 which shows a delivery pipe above the pump with a telescoping section. The wall of the inner pipe is slotted while the wall of the outer pipe is solid. When the parts are in a collapsed or compressed mode, the slots are closed. When they are extended they are open for drainage. Shear pins hold the parts in a compressed or closed mode during normal use. If a force is applied exceeding the strength of the pins, the pins shear, the slots are uncovered and the pipe is drained. Shoulders are provided to limit travel of the parts whereby, after the slots are uncovered, continued pulling extracts the pipe and pump. The entire assembly must be pulled out of the well in order to close the valve and replace the shear pins.
Other examples of earlier structures that can be found in the prior art are shown in U.S. Pat. Nos. 300,880, 1,213,776, 2,674,200 and 3,292,555.
All of the foregoing are useable, but they have the common disadvantage that upon activation of the release valve, the pump, waterline and valve must be removed from the well in order to reactivate the valve. Thus, the pipe cannot be drained for the sole purpose of flushing the line of sand and other debris or for the purpose of determining whether the pump is functioning properly.